1. Field of Invention
The present invention relates to an organic electroluminescent device and method for manufacturing thereof. In particular, it relates to a stacked organic electroluminescent device (Stacked OLED) and method for manufacturing thereof.
2. Description of Related Art
The organic electroluminescent device (OLED) is a device using the luminescent characteristic of organic functional materials for providing display purposes, its luminescent structure typically is constructed of a pair of electrodes and organic functional material layers. As the current passes through the area between the anode and the cathode, the electrons and the holes in the organic functional material layers are recombined to produce photons, thus allowing the organic functional material layers, according to its material characteristics, to produce light emitting mechanisms for the different emitting colors.
In the manufacturing process of the full color spectrum organic emitting device, the conventional technology fabricates a plurality of red (R), green (G), and blue (B) organic luminescent structures. In addition, the aforementioned R, G, B organic luminescent structures are assorted to produce an organic emitting device with full color spectrum results. But, in this kind of full color spectrum organic emitting device, the diminishing life cycles and the luminescent brightness of each color of organic functional material are different. Therefore, the organic emitting device faces issues regarding discrepancies in luminescent purity or in brightness for each color.
To solve the aforementioned issues, researchers have proposed a multilayer stacked OLED for producing single-colored light or white light organic electroluminescent device with higher luminant efficiency. It takes several single-colored light or white light organic electroluminescent devices stacked together to increase their luminant efficiency. FIG. 1 illustrates a schematic diagram for a multilayer stacked OLED. Referring to FIG. 1, this multilayer stacked OLED 100 has a substrate 110, a pair of electrodes 120, 130, a plurality of organic emitting layers 140, and a plurality of electrically conductive layers 150. The organic emitting layers 140 are mutually stacked. In addition, the electrically conductive layers 150 are located between each two organic emitting layers 140. As the current passes through the area between the electrodes 120, 130, the electrons 160, and the holes 170 in each organic emitting layer 140, will be recombined to form a photon 180. Therefore, as illustrated in FIG. 1, via the compounding effect of the photons 180, the luminant efficiency for the multilayer stacked OLED 100 is thus improved. But the structure illustrated in FIG. 1 only shows the single-colored light or white light, the demands for full color spectrum cannot be achieved.